1. Field of the Invention
The present invention generally relates to a coordinate input device for detecting a set of coordinates of a position of a contact on a position-sensitive surface. The present invention particularly relates to a coordinate input device which can simulate various mouse button operations.
A touch screen or a touch panel is a type of coordinate input devices that can be used as a position detecting device of a personal computer. In operating the personal computer, the user may simply touch objects, such as icons, displayed on a display. The touch screen may be of any type described below. One type of touch screen may include an upper conductive layer and a lower resistive layer overlaid on the upper conductive layer with a gap between the layers. Other types of the touch screen may include an upper resistive layer provided with a pair of parallel electrodes and a lower resistive layer provided with a pair of parallel electrodes arranged perpendicular to the pair of electrodes on the upper resistive layer. The upper and lower layers come into contact when there is a touch on the touch screen. The touch screen outputs coordinate information of the position of a touch, and basically operates as a single switch.
2. Description of the Related Art
It is known to place a coordinate input device such as a touch screen over a display face in order to specify a position on the display face.
The touch screen determines whether the upper and lower layers are in contact and then obtains the coordinate of the position of contact based on an electric potential distribution. Thus, the touch screen realizes operations such as positioning a cursor to a specified position displayed on the display. The touch screen of the related art can only determine whether or not the upper and lower layers are in contact. That is to say, only an ON/OFF representation is possible with the touch screen of the related art. Thus, the touch screen of the related art only serves as one switch.
When the touch screen is used with an OS (Operating System), such as Windows, based on a GUI (Graphical User Interface), a touch can only represent either a right button or a left button of a mouse.
Various techniques have been developed in order achieve a plurality of functions with the touch screen. For instance, with Windows CE, a touch on the touch screen panel corresponds to a left button operation of the mouse, and a touch on the touch screen simultaneous with an operation of a predetermined key of the keyboard corresponds to a right button operation of the mouse.
With a Windows system, when an icon displayed in a task tray is touched and the same icon is touched again directly after the first touch, it is identified as an operation of the right button. Thus, a plurality of functions can be represented.
Also, for a touch screen used with a dedicated retractable pen, retracting the tip of the pen represents the left button operation and pressing a button provided on the pen represents the right button operation.
However, with the coordinate input device of the related art, a touch on the touch screen is not sufficient for achieving the coordinate input operation and two button operations. Therefore, with the coordinate input device of the related art, it is necessary to use a further input device having two buttons to achieve two button operations.
Thus, in order to achieve the two button operation by the touch screen, it is necessary to use further input devices such as a dedicated pen or a keyboard. This results in an increased cost of a computer, when mounted on the computer such the notebook-type personal computer.
Further, it is known to configure a touch screen such that a touch on the touch screen corresponds to the left button operation. Then, such left button operation will be executed even in cases where it is simply required to designate a coordinate of a certain position. This then becomes an awkward function.
It is also possible to provide a predetermined region on the touch screen such that this region corresponds to the right button. With this structure, the right button operation is realized by touching the predetermined region on the touch screen. However, this results in complicated operations.
Accordingly, it is a general object of the present invention to provide a coordinate input device which can avoid complicated operations.
It is another and more specific object of the present invention to provide a system which can generate information corresponding to operations of various switches of a mouse.
In order to achieve the above objects according to the present invention, there is provided a touch screen unit comprising:
a touch-sensitive panel outputting voltage signals concerning a position of a contact made thereon; and
a control unit generating coordinate information and operation information of the contact based on said voltage signals,
wherein said operation information corresponds to operations of two or more switches.
With the system described above, a coordinate input device such as a touch screen can implement various operations which may correspond to right and left button operations of a mouse.
The present invention also provides a method of generating information corresponding to operations of two or more switches based on a state of contact on the position-sensitive surface. Further, the present invention provides a machine readable medium storing program code means for implementing such a method.
Other objects and further features of the present invention will be apparent from the following detailed description when read in conjunction with the accompanying drawings.